JP2023088546A - Joint structure for steel pipe pile - Google Patents

Abstract

To provide a joint structure for steel pipe piles that facilitates connection work.SOLUTION: A joint structure includes a first joint connected to an end of a first steel pipe pile, a second joint connected to an end of a second steel pipe pile, and a pin, and is configured to connect the first joint and the second joint by the pin. The first joint and the second joint are provided with a pin hole penetrating both when they are fitted together. The pin comprises: a pin body inserted into the pin hole; a flexible portion provided at a tip of the pin body, having a larger diameter than that of the pin hole in an unloaded state, engaged with a peripheral edge of an inner peripheral side opening of the pin hole, and reduced in diameter when the pin body is inserted into the pin hole; and a projection formed on the other end of the pin body and engaged with a periphery of an outer peripheral side opening of the pin hole.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to improvements in joint structures for steel pipe piles.

Steel pipe piles for building and civil engineering work are added according to the condition of the ground and driven to a desired depth.
Various measures have been proposed for connecting steel pipe piles. One aspect is a structure in which joints are connected to the upper end of the lower steel pipe pile and the lower end of the upper steel pipe pile, and the two are connected with pins ( Patent Document 1, Patent Document 2).

JP 2021-161662 A JP 2014-031717 A

The pin used in the joint structure disclosed in Patent Document 1 has a bolt structure, and by screwing this bolt into a fixing plate welded to the inner peripheral surface of the fitted joint, the joint of the upper and lower steel pipe piles is made. (Fig. 1, citing Fig. 2 of Patent Document 1).
When a bolt is used as a pin in this way, a sufficient torque is required for the threaded portion of the bolt, so a thick bolt shaft is required, which increases the cost and tightening work is troublesome.
In the joint structure of Patent Document 2, a thin bolt is passed through the pin (Fig. 2, referring to Fig. 1 of Patent Document 2). It takes

The present invention has been made to solve these problems, and the first aspect thereof is defined as follows. Namely
A first joint connected to the end of the first steel pipe pile, a second joint connected to the end of the second steel pipe pile, and a pin, wherein the first joint and the second joint are connected by the pin. A joint structure for connecting steel pipe piles,
The first joint and the second joint are provided with a pin hole penetrating through the first joint and the second joint when they are fitted together,
a pin body inserted into the pin hole;
A flexible portion provided at the tip of the pin body, which becomes larger in diameter than the pin hole in an unloaded state and engages with the peripheral edge of the inner peripheral side opening of the pin hole, thereby moving the pin body to the pin. a flexible portion whose diameter is reduced when inserted into the hole;
a projection formed on the other end of the pin body, the projection being engaged with the peripheral edge of the outer peripheral side opening of the pin hole;
A steel pipe pile joint structure comprising:

According to the coupling structure of the first aspect defined in this way, the flexible portion provided at the tip of the pin body engages the peripheral edge of the inner peripheral side opening of the pin hole, and the other end of the pin body engages. Since the provided protrusion engages with the peripheral edge of the outer peripheral side opening of the pin hole, the fitted first and second joints are connected. By imparting an elastic repulsive force to the flexible portion, the connection between the two becomes stronger.
Since the diameter of the flexible portion is reduced when the pin main body is inserted into the pin hole, it does not interfere with the insertion work. In other words, the work of inserting the pin into the pin hole from the outer peripheral side of the joint fitting body of the first joint and the second joint is performed by pushing the other end of the pin body with the tip of the pin body facing the pin hole. You can hit it with a hammer or the like. This simplifies the work of connecting the joint fitting bodies using the pins. Since the projection provided at the other end of the pin body engages with the peripheral edge of the opening on the outer peripheral side of the pin hole, the pin body is prevented from falling out to the inner peripheral side of the joint fitted body due to excessive hammering. In addition, the position of the flexible portion is also fixed by fixing the position of the other end of the pin body by engaging the projection with the peripheral edge of the outer peripheral opening, thereby fixing the position of the flexible portion with respect to the peripheral edge of the inner peripheral opening of the pin hole. Engagement of the flexible portion is stabilized.

A second aspect of the invention is defined as follows. Namely
In the joint structure defined in the first aspect, in the pin body, the distance from the projection to the tip is longer than the pin hole, and the tip is positioned in the pin hole when the pin body is inserted into the pin hole. more prominent,
The flexible portion is made of a flexible steel material, and includes a fixed portion fixed to the tip portion, and a flexible portion main body connected to the fixed portion, and protrudes outward from the tip portion. a flexible portion main body having an engaging portion that engages with a peripheral edge of an inner peripheral side opening of the pin hole.

According to the coupling structure of the second aspect defined in this way, by projecting the tip of the pin body from the inner peripheral side opening of the pin hole, the engaging portion of the flexible portion attached to the tip is attached to the pin. released from the hole. As a result, the engaging portion reliably engages with the peripheral edge of the inner peripheral side opening.
On the other hand, unless the tip of the pin body protrudes from the pin hole, the engagement between the engaging portion of the flexible portion body and the inner peripheral side opening of the pin hole becomes unstable. This is because there is a possibility that the engaging portion may not be completely removed from the pin hole.

A third aspect of the present invention is defined as follows. Namely
In the coupling structure defined in the second aspect, a recess is provided in the peripheral edge of the tip of the pin body, and the engaging portion of the flexible portion body is accommodated in the recess in the pin hole. It engages with the rim of the opening on the inner peripheral side.
According to the coupling structure defined in this way, the engaging portion of the flexible portion main body is accommodated in the recess formed in the peripheral edge of the tip of the pin main body, and engages with the peripheral edge of the inner peripheral side opening of the pin hole. match.

Since the tip of the pin body protrudes from the inner peripheral surface of the joint fitting body, in order to engage the engaging portion of the flexible portion attached to the tip with the peripheral edge of the inner peripheral side opening of the pin hole, A barb (a portion extending from the tip of the pin main body toward the root side) is required in the engaging portion of the flexible portion according to the length of projection. This barbed portion acts as a resistance when the pin is inserted.
Here, by providing a concave portion in the tip portion and housing the engaging portion therein, resistance during insertion of the pin can be reduced.
Further, by providing a concave portion and housing the engaging portion therein, the position of the engaging portion can be brought closer to the peripheral edge of the opening on the inner peripheral side of the pin hole. In other words, the distance between the engaging portion and the side surface of the pin body can be reduced. As a result, the amount of diameter reduction of the flexible portion during insertion of the pin can be reduced, and in this respect also resistance during insertion of the pin can be reduced.

A fourth aspect of the present invention is defined as follows. Namely
In the joint structure defined in the third aspect, the recess reaches the pin hole in the axial depth of the pin body with the pin body inserted into the pin hole, and reaches the pin hole in the radial depth. , the outermost portion of the engaging portion facing the recess when the pin body passes through the pin hole is accommodated.
According to the joint structure of the fourth aspect defined in this way, since the concave portion reaches up to the pin hole in the depth in the axial direction of the pin body, The engaging portion can be reliably engaged. The recess is sufficiently deep in the radial direction of the tip so that the entire engaging portion is housed in the recess when the pin body passes through the pin hole. This further reduces the resistance when driving the pin into the pin hole.

A fifth aspect of the present invention is defined as follows. Namely
In the joint structure of the fourth aspect, the flexible portion is an M-shaped linear or thin plate-shaped member, and the center portion of the M-shape is fixed to the center of the tip portion in a state where it rises from the tip portion of the pin body. In an unloaded state, both ends of the M-shape are accommodated in the recess as the engaging portion, while the lower end of the M-shaped portion is exposed from the recess in the outer peripheral direction and engaged with the peripheral edge of the inner peripheral side opening of the pin hole. do.
According to the joint structure of the fifth aspect defined in this way, the structure of the flexible portion can be simplified.

FIG. 1 is a sectional view showing a conventional joint structure. FIG. 2 is an exploded perspective view showing another conventional joint structure. FIG. 3 is a cross-sectional view showing a connecting structure of steel pipe piles according to one embodiment of the present invention. FIG. 4 shows the pin of the embodiment, FIG. 4(A) is a front view, (B) is a right side view, (C) is a left side view, and (D) is a bottom view. FIG. 5 is a partially enlarged view showing the structure of the recess.

Embodiments of the present invention will be described below with reference to FIGS.
FIG. 3 is a cross-sectional view showing a joint structure 1 according to one embodiment of the present invention. In the figure, reference numerals 3 and 5 denote steel pipe piles. A first joint 10 is welded to the first steel pipe pile 3 on the upper side, and a second joint 20 is welded to the second steel pipe pile 5 on the lower side. In this example, the same diameter is adopted for the first steel pipe pile 3 and the second steel pipe pile 5, but they can also be made different diameters.

The first joint 10 comprises a joint base 11 , an outer ring portion 13 and an inner ring portion 15 . The joint base 11 is thicker than the first joint 10, the outer ring portion 13 and the inner ring portion 15, and the lower end of the first steel pipe pile 3 is welded through an opening to the center of the upper surface thereof. The outer ring portion 13 and the inner ring portion 15 are welded to the outer edge of the lower surface and the inner edge of the lower surface through openings, respectively. A pin hole 17 is formed in the outer ring portion 13 and a pin hole 18 is formed in the inner ring portion 15 .

The lower edge of the second joint 20 is welded to the upper end of the second steel pipe pile 5 through an opening. A pin hole 21 is formed in the second joint 20 .
A pin hole 21 may be drilled directly into the upper end portion of the second steel pipe pile 5 and inserted into the first joint 10 . In this case, the upper end portion of the second steel pipe pile 5 becomes the second joint. In other words, the second joint may be integrally connected to the second steel pipe pile.
By inserting the second joint 20 between the outer ring portion 13 and the inner ring portion 15 of the first joint 10, a joint fitting body of the first joint 10 and the second joint 20 is formed. The pin holes 17, 21, 18 communicate with each other.

Pins 30 are inserted into these pin holes 17 , 21 , 18 .
The pin 30 has a pin body 31 , a flexible portion 40 and a projection 50 .
The pin body 31 is a cylindrical member having a diameter slightly smaller than the diameter of the pin hole, and has a flexible portion 40 at its tip portion 33 and a projection 50 on the peripheral edge of the other end portion 35 .
As shown in FIG. 4, the flexible portion 40 is made of a member obtained by bending a linear spring steel into an M shape, and the lower edge of the central portion (fixed portion 41) of the M shape is the tip portion 33 of the pin body 31. welded to the central part of the

A pair of flexible portion main bodies 43 rises from the fixed portion 41 toward the tip end side of the pin main body 31 in the axial direction and is bent outward. The distal end (engagement portion 45 ) of each flexible portion body 43 protrudes outward from the distal end portion 33 of the pin body 31 . In other words, the diameter of the flexible portion 40 is larger than that of the distal end portion 33 in an unloaded state.
A concave portion 37 is provided at a position facing the engaging portion 45 on the peripheral edge of the distal end portion 33 . A part of the inner peripheral side of the engaging portion 45 in the unloaded state is accommodated in the concave portion 37 . The lower end of the engaging portion 45 protrudes outward from the concave portion 37 and thereby engages with the peripheral edge of the inner peripheral side opening of the pin hole 18 (see FIG. 5). The lower end of the engaging portion 45 is also accommodated in the recess 37 , so that it is located closer to the root side of the pin body 31 (the other end portion 35 side) than the tip portion 33 .

The recess 37 has a depth U1 in the axial direction of the pin body 31 . The depth U1 is larger than the length of the pin body 31 protruding from the pin hole 18 (protrusion amount L). By housing the portion of the flexible portion main body 43 following the engaging portion 45 in the recess 37, the position of the engaging portion 45 can be brought as close to the periphery of the opening of the pin hole 18 as possible.
The recess 37 has a depth of U2 in the radial direction of the tip 33 of the pin body 31 . The depth U2 is such that the outer periphery (outermost portion) of the engaging portion 45 is accommodated in the recess 37 when the pin 30 is driven into the pin hole. This reduces the drive-in resistance of pin 30 .

A pair of protrusions 37 are formed on the periphery of the other end portion 35 of the pin body 31 . By setting the distance between the protrusion 37 and the engaging portion 45 to be the same as the thickness of the first joint 10, the joint fitting body of the first joint 10 and the second joint 20 can be firmly connected by the pin 30 without backlash. .
In this example, as shown in FIG. 4C, the protrusion 50 is provided at a position shifted by 90 degrees from the recess 37 in side view, but the position and number of protrusions are not particularly limited.

The construction method of this joint structure is as follows.
A first joint 10 is preliminarily welded to the lower end of the first steel pipe pile 3 , and a second joint 20 is preliminarily welded to the upper end of the second steel pipe pile 5 .
After embedding the second steel pipe pile 5 in the ground, the first joint 10 of the first steel pipe pile 3 is fitted to the second joint 20 thereof. Pin holes 17, 21, and 18 of each joint are made to penetrate, and a pin 30 is driven in from the outer peripheral side.

Since the flexible portion 40 fixed to the tip portion 33 of the pin body 31 is M-shaped, it can be inserted into the pin hole 17 from the tip side without resistance. After being inserted into the pin hole 17, the pin 30 interferes with the peripheral edge of the pin hole 17 and is reduced in diameter.
With the tip 33 of the pin body 31 protruding from the pin hole 18 , the engaging portion 45 is released from interference with the peripheral surface of the pin hole 18 , expands in diameter, and engages with the peripheral edge of the opening of the pin hole 18 . .

In the above description, the M-shaped flexible portion has been described as an example, but the present invention is not limited to this.
A part of the flexible steel material is fixed to the tip of the pin body, and a part of it protrudes outward from the tip of the pin body and engages with the rim of the opening on the inner peripheral side of the pin hole of the joint. It can be designed arbitrarily as long as it fits and can be reduced in diameter when the pin is inserted to reduce the insertion resistance.

The structure of the joint is also not limited to the example shown in FIG. For example, the structure which welds one ring-shaped coupling|joint to each of a 1st steel pipe pile and a 2nd steel pipe pile, and makes them fit may be sufficient.
As described above, the present invention is not limited to the above embodiments, and can be appropriately modified within the scope of those skilled in the art without departing from the scope of claims.

1 joint structure 3 first steel pipe pile 5 second steel pipe pile 10 first joint 20 second joint 17, 18, 21 pin hole 30 pin 31 pin main body 33 tip portion 35 other end portion 37 concave portion 40 flexible portion 41 fixed portion 43 Flexible portion main body 45 Engagement portion 50 Protrusion

Claims (5)

A first joint connected to the end of the first steel pipe pile, a second joint connected to the end of the second steel pipe pile, and a pin, wherein the first joint and the second joint are connected by the pin. A joint structure for connecting steel pipe piles,
The first joint and the second joint are provided with a pin hole penetrating through the first joint and the second joint when they are fitted together,
a pin body inserted into the pin hole;
A flexible portion provided at the tip of the pin body, which becomes larger in diameter than the pin hole in an unloaded state and engages with the peripheral edge of the inner peripheral side opening of the pin hole, thereby moving the pin body to the pin. a flexible portion whose diameter is reduced when inserted into the hole;
a projection provided on the other end of the pin body, the projection engaging the peripheral edge of the outer peripheral side opening of the pin hole;
A steel pipe pile joint structure comprising: a distance from the projection to the tip of the pin body is longer than the pin hole, and the tip protrudes from the pin hole when the pin body is inserted into the pin hole;
The flexible portion is made of a flexible steel material, and includes a fixed portion fixed to the distal end portion, and a flexible portion main body bulging outward from the fixed portion on the inner peripheral side of the pin hole. 2. The coupling structure according to claim 1, further comprising a flexible portion main body having an engaging portion that engages with the periphery of the opening. A concave portion is provided on the peripheral edge of the tip of the pin body, and the tip of the flexible portion main body serves as the engaging portion, and the peripheral edge of the inner peripheral side opening of the pin hole is accommodated in the concave portion. 3. The coupling structure according to claim 2, which engages with the The recess reaches the pin hole with the pin body inserted into the pin hole at the axial depth of the pin body, and the front pin body passes through the pin hole at the radial depth. 4. The joint structure according to claim 3, wherein an outermost portion of said engaging portion facing said concave portion is accommodated when connecting said engaging portion. The flexible portion is an M-shaped linear or thin plate-shaped member. 5. The pin hole according to claim 4, wherein both ends of the letter are accommodated in the recess as the engaging portion, and the lower end thereof is exposed from the recess in the outer peripheral direction and engaged with the peripheral edge of the inner peripheral side opening of the pin hole. joint structure.

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